SPRABJ8B September   2022  – November 2023 AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1 , AM263P4 , AM263P4-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
    1. 1.1 Acronyms
  5. 2 Power
    1. 2.1 Discrete DC-DC Power Solution
    2. 2.2 Integrated PMIC Power Solution
    3. 2.3 Power Decoupling and Filtering
    4. 2.4 Power Consumption
    5. 2.5 Power Distribution Network
      1. 2.5.1 Simulations
        1. 2.5.1.1 Core Digital Power 1.2 V
        2. 2.5.1.2 Digital/Analog I/O Power 3.3 V
    6. 2.6 e-Fuse Power
  6. 3 Clocking
    1. 3.1 Crystal and Oscillator Input Options
    2. 3.2 Output Clock Generation
    3. 3.3 Crystal Selection and Shunt Capacitance
    4. 3.4 Crystal Placement and Routing
  7. 4 Resets
  8. 5 Bootstrapping
    1. 5.1 SOP Signal Implementation
    2. 5.2 OSPI/QSPI Memory Implementation
    3. 5.3 ROM OSPI/QSPI Boot Requirements
  9. 6 JTAG Emulators and Trace
  10. 7 Multiplexed Peripherals
  11. 8 Digital Peripherals
    1. 8.1 General Digital Peripheral Routing Guidelines
  12. 9 Analog Peripherals
    1. 9.1 General Analog Peripheral Routing Guidelines
      1. 9.1.1 Resolver ADC Routing Guidelines
  13. 10Layer Stackup
    1. 10.1 Key Stackup Features
  14. 11Vias
  15. 12BGA Power Fan-Out and Decoupling Placement
    1. 12.1 Ground Return
    2. 12.2 1.2 V Core Digital Power
      1. 12.2.1 Key Layout Considerations
    3. 12.3 3.3 V Digital and Analog Power
      1. 12.3.1 Key Layout Considerations
    4. 12.4 1.8 V Digital and Analog Power
      1. 12.4.1 Key Layout Considerations
  16. 13References
  17.   Revision History

3.1 Crystal and Oscillator Input Options

The AM263x and AM263Px XTAL_XI and XTAL_XO (pins T1 and R1) clock input can be sourced from either an attached crystal or a single-ended oscillator output. The attached crystal should be a fundamental mode crystal operating at 25 MHz. If operating from a single-ended oscillator output, the XTAL_XI pin should be connected to the oscillator and the XTAL_XO pin must be left floating, unconnected on the PCB. In oscillator input mode, the XTAL_XI pin can be tied to either a 1.8 V square-wave or sinewave oscillator. For full crystal and oscillator input requirements, see the AM263x Sitara™ Microcontroller Data Sheet or AM263Px Sitara™ Microcontroller Data Sheet.

GUID-20220808-SS0I-29HS-WMT8-14ZPTXK4FFXS-low.png Figure 3-1 Excerpt From AM263x Control Card Schematics (for full crystal and oscillator input requirements)

In the case of the AM263x Control Card, an onboard ABM10W-25.0000MHZ-8-K1Z-T3 25 MHz crystal provides crystal mode clocking. Alternatively, an LMK1C1104PWR clock distributor circuit and SN74LV1T34 buffer provide the 1.8 V square-wave clock to the XTAL_XI pin. The LMK1C1104PWR is also used to provide a clock source to the onboard Ethernet PHY as well.

GUID-20220808-SS0I-7CRT-X92R-F89HN5CHJR94-low.png Figure 3-2 Excerpt From AM263x controlCard Schematics - Oscillator Clock Source and Clock Distributor